Photonic rearrangeable networks with zero switching-element crosstalk

The substantial growth expected in the near future in the demand of transmission bandwidth to be used in a dynamic and flexible transport network makes the development of all-optical digital crossconnect architectures very important. We consider here in particular the class of the rearrangeable non-blocking space-division switching fabrics configured as multistage structures built with very simple optical switching elements. Rearrangeable networks look today more attractive than strict-sense non-blocking networks since the former have a lower complexity and are compatible with the data loss rate required in a circuit-switched network even with current technology of optical switching devices. We face one the most important problems which arises in a multiple space-channel optical system such as a photonic switching fabric, that is the build-up of crosstalk noise on a certain channel due to the interference with other signals inside the system. We find here the design rules to configure a minimum-cost rearrangeable photonic switching network where the most serious cause of crosstalk (interference inside the switching elements) is eliminated